There are many advantages in using non-intrusive (clamp-on) type ultrasonic flow meters some of which are:

fast & inexpensive installation without pipe cutting
can measure aggresive or toxic liquids
can measure high temperature liquids •can measure conductive & non conductive liquids
will not contaminate liquids
inexpensive maintenance

Some common applications for ultrasonic flow meters are:

Aerospace

Test measurements with high sampling rate
Diesel and fuel oils
Hydraulic oil
Chemicals and solvents
Abrasives
Acids and caustics
Cooling water

Building Services

HVAC and Energy
Utilities monitoring
Effluent discharges
Water/glycol solutions
Potable water

Chemical industry

Non-invasive measurement of aggressive/toxic media .
Operational measurements of non-conductive media
Mobile flow checks during plants start-up and inspection . On site flowmeter checking

Chiller/Refrigeration Systems

Inlet outlet flows
Preventative maintenance and pump checks to protect / verify existing packages

Food and drink industry

Hygienic measurements on clear liquids, juices and syrups

Manufacturing and process industries

Detection of leakage on hydraulic plants
Machine cooling and lubrication systems
Monitoring of cooling and heating circuits and of pumps. Numerous hydraulic applications

Marine

Diesel and fuel oils
HVAC
Pump monitoring

Oil and Gas exploration

Measurements on high-pressure systems
Crude oil flow measurements on oil rigs .-Mud Applications and Produced Water. High Pressure Gas Applications (more than 600 PSI)-Well testing and Production testing-Water Cut analysis-Water Oil concentration measurements-Brine and cement flow measurement